1. Field of the Invention
The present invention relates to heating devices and radiator elements which are part of the heating device. The invention further relates to corresponding manufacturing processes. The invention particularly relates to heating devices that are used for heating air.
2. Description of the Related Art
In motor vehicles, particularly those having fuel consumption optimized combustion engines, heating devices or radiators are used for heating the passengers compartment and the engine. However, heating devices are also suitable for other purposes of use in a wide area of application, e.g. in the household installation (air conditioning), industrial plants etc.
Usually, heating devices, in particular heating devices having PTC (Positive Temperature Coefficient) heating elements (i.e. PTC resistors) have radiator elements serving for providing a heat flow for cooling. The heat transfer is often supported by an air flow generated by a blower.
Radiator elements of this type are known to exist in different forms. Many conventional radiator elements for instance comprise lamellae that are fixed by soldering to holding sheets or cover sheets or that are attached to these sheets in a different way. The manufacturing of soldered designs does, however, require great effort and is also not reliable with respect to its processing since it often occurs that not all contact points of the lamellae are soldered on and a regular heat flow transport does therefore not take place.
This may affect the thermal output of the (PTC) radiator to such a great extent that the radiator can no longer be operated within the predefined specification.
As an alternative to the soldered radiator elements, mechanical fixings such as clamping connections are also known. However, these connections reveal the disadvantage that the installation of such radiator elements or the radiator is expensive and error prone.
A radiator is known from EP 0 575 649 B1 which contains heating elements composed to form prefabricated units, where the heating elements consist of sheet strips joined by riveting which include a lamella strip. The PTC elements used are held in windows or break-through openings of plastic frames. For installation, the prefabricated heating element units and the plastic frames provided with the PTC elements are laminated and fixed by means of a support frame. This component reveals the disadvantage that the installation of a radiator of this type is costly.
DE 197 06 199 A1 also describes an electric heating means, in which the heating elements with corrugated ribs carrying PTC elements are laminated. Projections on the sheets serve for securing the position of the corrugated ribs between the heating elements, said sheets bordering the PTC elements. This measure does also not lead to an improved assembly.
EP 0 379 873 A2 describes a device for heating gases by using PTC elements that are set in a frame member which is encompassed by a U-profile and that is covered by a cover plate. Lamellae are arranged in a frictionally tight manner on the arrangement for discharge of heat to the surrounding air, said Lamellae having a breakthrough for this purpose. Although heating units are thereby created on which thermal output elements are arranged, a device of this type can, however be assembled in a costly manner only, since the lamellae have to be slip on separately. Moreover, the arrangement is less stable and cannot easily be laminated.
EP 1 061 776 A1 describes a heating device for heating the air, which comprises position frames with means for the snap-tight locking of radiator elements and electrode sheets. The position frames thereby enable the joining to form radiator units, which can subsequently be laminated or stacked. PIG elements are used as heating elements. Crimp brackets serve for attaching lamellae elements to radiator sheets.